I am prior service Army (released from active in May 2020) and want to join the ANG to tryout for TACP. Care to enlighten me?

Air National Guard is still a Reserve Component. You don't PCS, there's not a choice of base or anything like that. You work at the base closest to you where your job is.

A few seconds of Google search will tell you what you need to know about the ANG AGR program

https://www.ang.af.mil/Careers/State-Active-Guard-Reserve/

I have a friend that Recruited for the Air Guard. They don't have an Active TACP unit. They have admin jobs at all reserve units that you can try to obtain but it is a bit of a process and they are highly desired. You may try to deploy by volunteering to go with an active unit but if you don't have the rating they need then you won't go. You rank is not as important as your qualifications in the TACP land. They are not all the same. TACP is a challenging job. I know they seek out combat arms but they have a bit of a wash out rate. They have a selection school if I am not mistaken now.

TACTICAL AIR CONTROL PARTY MISSION

Tactical Air Control Party members are part of the Special Operations team that lives by the motto: "Advise, Assist, and Control". They diligently work at protecting America and its allies in the global war on terrorism. These specialists are easily identifiable as they have earned the right to wear the coveted black beret. They provide numerous critical functions on the modern battlefield, including advising ground forces on aircraft deployment and capabilities, coordinating and controlling aerospace operations, and participating in battle planning.
https://www.goang.com/discover-ang/missions/special-operations/tactical-air-control-party-mission.html

Good questions. Great answers. I went from AD Army to ARNG and then ANG and then AFR. You will most likely take the ASVAB again. It is imperative to do very well. The better your score the more desirable you are to recruit and the more options you have for cross-training. You are not restricted as a Traditional Guardsman from joining any installation in the country you choose however, it is travel by your own means for normal weekend training and the base closest to you may not have your desired specialty. This is typical for pilots especially if they work for the airlines, FedEx, UPS etc the have flight benefits. I traveled on my own dime to be in the units I desired after leaving my hometown unit. Some were just 100 miles others were 400 and 600. If your specialty is listed on the critical manning list for your desired location then the cost of your travel will (can) be reimbursed. It is published annually. You are also reimbursed for annual training travel and orders of any kind but these have an impact on unit funds and federal funds and can change dramatically over time (manning is met) and administrations. It can also impact your selection for orders based on the same funding considerations since in addition to travel, on and off-base lodging accommodations and rapid response are considered in many cases. I strongly advise visiting and reviewing the unit you are interested no matter where it is before choosing as well. Talk to the people you will be working with and for. It is important to both you and the gaining unit that you are a good fit. Do not rely only on the recruiters for information. I went to the local base for 9 years trying to find an open position but there never was a vacancy. I met an airman who suggested I join his unit and told him of my attempts. He laughed and said to ask for his Chief by name and visit him. I did and introduced myself dropping his name as a reference and talked about my experience and background and he directed me to the recruiter saying" tell them I sent you." They again said there were no vacancies until I told them the Chief sent me and everything changed. That should have been a red flag of course but I gained a great deal of KSA all around.

TACTICAL AIR CONTROL PARTY (TACP)

If you're up for the extreme challenge, becoming a Tactical Air Control Party (TACP) Specialist is one of the most rewarding jobs the Air National Guard offers. You'll have to meet strenuous entry requirements, but if you do, you'll become qualified as an Airborne Ranger, proficient in air assault, skilled in scuba operation, and trained in parachute tactics. You'll maintain the highest physical and mental standards that you'll need as you will be imbedded on the front lines of war with Army and Marine Special Forces units providing tactical air support for ground attack fighters. As a TACP, you and your team will directly engage enemy forces, using advanced technology and weapons systems to direct air strikes, sometimes in close proximity to friendly forces. You'll control and execute operational air and space power, and most of the time, you'll be in austere combat environments independent of an air base or its perimeter defenses.

MINIMUM EDUCATION: NONE
CATEGORY: COMMAND AND CONTROL
AFSC CODE: 1C4X1
LOCATIONS WITH THIS CAREER TYPE (12)

https://www.goang.com/careers/command-and-control/tactical-air-control-party-tacp.html

1) No re-do of basic training is required except for select special circumstances. You do not seem to fall into any of those.
2) If I understand your question, yes.
3) No. Only specialty (TACP for you) availability and vacant slots, unless you mean AGR (Active Guard and Reserve). That's a whole other animal.
4) I'm not a former TACP but I had an Airman that transferred to that AFSC. Basically, washout rate is 70% and up. Very high level of physical fitness, high tolerance to pain and discomfort, extreme focus and an unstoppable will to complete the mission and achieve the goal. If this makes you uneasy, it's not for you.

I am a current Air Guard member.
The first place to start is here>>> https://www.goang.com/content/goang/en/locations.html
You can look at the AFSC's near where you are. It also lists the recruiter's point of contact info for that state.
1. Nope
2. It is your choice where you live but remember if live in Vermont and drill in Alabama it's your dime that covers the travel costs. I did Virginia to Florida for 18 months.
3. Depends on the mission and the unit. In my last unit it was fairly easy they had lots of AGR slots. In the current unit, it is harder to be active.

I served in a National Guard Airborne Infantry LRS unit and one of my troopers applied and was accepted to Delta evaluation. Nothing is impossible. Gco. 143rd LRS.